Labyrinth seal ring for pulp refiner

ABSTRACT

A disc refiner wherein there are means for channelling solids to its rotary discs for refining therebetween and discharge characterized by sealing means inhibiting unrefined solids from by-passing the discs and discharging with the refined material. The sealing means includes a labyrinth passage and provides for use of fluid under pressure serving as a dynamic dam for blocking and maintaining unrefined solids in their required line of flow. In certain instances the fluid will serve also as a lubricant between relatively moving parts.

United States Patent [191 Horstman et al.

LABYRINTH SEAL RING FOR PULP RElFlNElR Inventors: Anton J. Horstman; William M.

McNeil, both of Springfield, Ohio Assignee:- The Bauer Bros. Co., Springfield,

Ohio

Filed: Oct. 13, 1972 Appl. No.2 297,177

U.S. Cl. 241/244, 277/57 Int. Cl. 1302c 7/11 Field of Search, 277/74, 75, 70, 72, 57'

References Cited UNITED STATES PATENTS 2/1902 Copenhaver 277/70 UX g A disc refiner wherein there are means for channelling [11] 3,843,065 I451 Oct.22, 1974 Bunge 277/57 Horstman 277/134 X Primary Examiner-Samuel B. Ro'thberg Attorney, Agent, or Firm-Jerome P. Bloom ABSTRACT solids to its rotary discs for refining therebetween and discharge characterized by sealing means inhibiting unrefined solids'from by-passing the discs and discharging with the refined material. The sealing means includes a labyrinth passage and provides for use of fluid under pressure serving as a dynamic dam for blocking and maintaining unrefined solids in their required line of flow. In certain instances the fluid will serve also as alubricant between relatively moving parts,

8 Claims, 4 Drawing Figures PATENIEB 0m 22 an j LABYRINTH SEAL RING FORPULP ttEFtNER This invention relates to improvements in disc refiners. It more particularly provides a unique seal at the inlet to a refiner where a joint is produced between the refiner housing and a rotating disc. The benefits are two-fold. It inhibits a by-pass of unrefined solids to mingle with refined material and reduces the incidence of wear in the related components of the disc refiner.

BACKGROUND OF THE INVENTION Although not so limited in application, the invention has special utility in disc refiners which operate on fibrous solids to produce individual fibers and fiber aggregates for use in end products such as paper, fiber board and the like. In a device of this type the refiner ring on the relateddisc, both rings being of novel configuration. The mating surfaces of therings effectively define a pressure area or chamber wherein fluid is suitably applied to form a dam or repelling force inhibiting throughflow of solids. The, result is to effectively prevent contamination of the refined produce discharged from the refiner, to reduce the normal incidence of wear at the infeed joint, and to obviate excessive power case houses a pair of relatively rotatable discs. Normally the refiner case and one of the discs have communicating openings forming an inlet passage or feed conduit for fragmented solids in a slurry form to flow directly to and move radially outward between the operating faces of the refiner discs as they relatively rotate. The discs produce individual fibers and fiber aggregates which are radially discharged to the case interior, from which they exit as a refined product. There have been continuing and serious problems in such devices due to the tendency of unrefined solids to by-pass the refiner discs by moving radially outward through the joint between the case and the relatively rotating feed disc defining the feed conduit. The highly objectionable results are the contamination of the refined product by the unrefined solids and considerable wear at the joint through which the contaminating solids escape. Moreover, as material attempting to by-pass through the described joint becomes lodged therein, resulting frictional forces bring on increased power consumption and uncertain start-ups. The present invention is a solution to the above problems.

To understand the significance of the solution, it must be made clear that there is inherently high resistance to inflow as the feed material reaches and moves radially outward between the refiner discs. Multiply this resistance by the fact that in a pressurized, refiner case, the elevated pressure in the case interior adds its resistance factor. Particularly in the instance of the pressurized refiner, the pressure applied in delivering the feed material is required to be significant. There is accordingly an appreciable pressure drop in the case interior, which is directly reflected across the joint between the refiner case and the feed disc. It is this pressure drop that influences shives and other unrefined solids to seek to escape through this joint and thereby by-pass the refining discs. Keep in mind that in forming the joint there has to be a compromise between the need to avoid frictional contact and the need to limit penetration and passage of unrefined materials. This has plagued the industry.

SUMMARY OF THE INVENTION This invention not only obviates the above noted problems but has in view a generally improved means of providing the feed conduit in disc refiners. In practice, an embodiment is particularly characterized by means utilizing fluid pressure in the noted joint in a manner to preclude or block passage therethrough of any significant solids. As here prescribed the joint is defined by a seal ring on the refiner case and an entrance consumption and balky start-ups. As a matter of fact, the invention contemplates that in the process there will and can be a lubrication of the joint with attendant benefits.

A primary object of the invention is to provide improvements in the feed characteristics in disc refiners of the class described which are economical to effect and produce a unit more efficient and satisfactory in use, adaptable to a wide variety of applications and one unlikely to'malfunction.

A further object of the invention is to provide improvements of the infeed structure of a disc refiner which inhibit contamination of its discharge by unrefined solids.

Another object of the invention is to provide unique sealing means for use at a joint between relatively moving parts.

A further object of the invention is to provide in'a feed passage defined by relatively rotating parts and in a joint therebetween a pressure chamber utilizing fluid to block or repel passage of solids through such joint.

A still further object of the invention is to obviate problems brought on by the lodging of material in a joint in a materials feed passage.

An additional object of the invention is to provide an improved seal at a joint between relatively rotating parts possessing the advantageous structural features, the inherent meritorious characteristics and the means 7 and mode of use herein described.

With the above and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the drawings wherein some but not all embodiments of the invention are :shown,

FIG. 1 is a vertical section of a disc refiner embodying the invention;

FIG. 2 is a fragmentary section of FIG. 1 on an enlarged scale;

FIG. 3 is a view illustrating the operating face of the seal ring of the disc refiner; and

FIG. 4 is a view illustrating the operating surface of the entrance ring which cooperates with the seal ring.

Like parts are indicated by similar characters of refthe refiner will be limited to only those portions as may be required to understand the present invention.

As seen in the example illustrated, the refiner case comprises a unitary, central, tubular waist section sealed at its lower end by a dome-like bottom cap 13 and at its top or its other end by a dome-like cap 14. In their assembly the case elements are so connect ed to be suitably sealed together to'provide a chamber 15. Formed in a side wall 11 of the case section 10 is an inlet opening 12 and in its bottom cap 13 a discharge opening 16. Fixed to the wall 11 is an adapter providing a feed inlet chute 17. The chute 17 has formed therein an inclined feed passage 18 the lower end of which slurry embodying particles of raw solids is fed to and through the feedpassage 18 by way of suitable valve means which maintain a pressure sealof the chamber at inlet 12. A similar valve means handles the refined material in discharge thereof from the opening 16 amd maintains a pressure seal of the chamber 15 at its dischargeopening.

Openings in the upper and lower case sections, for inspection or drain, are conventionally provided with releasable sealing plugs.

Centered in the chamber 15 are relatively opposed refiner disc units 21 and 22. These disc units incorporate suitable means which define their refining surfaces which are positioned in closely adjacent, relatively opposed, spaced relation. The disc unit 21 mounts on one extremity of a drive shaft 23 which extends rearwardly thereof through. the center of inlet opening 12, the lower end of feed passage 18 and outwardly through a sealing gland 24 mounted in an opening in feed chute 17. The outer or other extremity of shaft 23 is coupled to and driven by a suitable motor (not shown). The disc unit 22 mounts on the inner end ofa similar drive shaft 23' which is co-axial with shaft 23 and extends through a sealing gland 24' in the wall of case section 10. The shaft 23' has its outer extremity coupled to a suitable drive motor (not shown).

It will be obvious that on energizing of their drive motors the drive shafts of the disc units may be independently and simultaneously driven and the disc units 21 and 22 relatively rotated.

Referring with more particularity to the wall portion 11 of case section 10, on its inner surface rimming the inlet opening 12 there is what appears to be a counterbore. This forms a wide shoulder 25, facing inwardly of the chamber 15, at the inner peripheryof which is the opening 12 and at the outer limit of which is a perpendicularly projected cylindrically formed wall surface 26. Secured to the shoulder 25, by bolts 27, is an annular sealing ring 28. The ring 28 has a generally rectangular cross section and fits snugly to and within the counterbore defined by wall surface 26. Bolts 27 are installed in wall apertures 29 and project into and are secured in threaded engagement with bores 31 in the ring 28. The bolts 27 are provided in an appropriately spaced apart circumferential series and are adjustable to have their head portions react on wall 11 and draw the sealing ring to positively seat on the shoulder 25.

The seal ring 28 has inner and outer peripheral portions, the latter contacting surface 26 and the former constituting a part of the flow channel from opening 12 to the disc assembly. The face of the ring 28 most adjacent the disc assembly is formed with a continuous annular groove or recess 32 which is generally rectangular in cross section, providing it with approximately parallel sides and a bottom which is perpendicular to the sides.

The disc unit 21, which is immediately adjacent to the inlet opening 12, is formed with a series of feed passages 33. These passages are circularly spaced immediately about the disc connection to the drive shaft 23 to open at one end, constituting their entrance end, at the rear face of the disc and to the inlet opening 12. The passages 33 diverge to open at their other ends at the inner periphery of the disc refining surface and to the complementary facing refining'surface of disc unit 22.

At the rear face of disc 21, immediately about the feed passages 33, the disc hasa counterbore in adjacent facing coaxial relation to that forming the shoulder 25. This counterbore provides a shoulder 34 which is positioned parallel to shoulder 25. At the outer periphery of shoulder 34 is a shallow cylindrically formed wall 35 disposing coaxial with wall surface 26. However, shoulder 34 has its inner periphery formed on a larger radius than the inner periphery of shoulder 25. Fixed to seat to the shoulder 34 and wall 35 is an entrance ring 36 formed as to its inner and outer peripheral dimension generally in accordance with that of the sealing ring 28,

. with respect to which it is in generally opposing parallel relation. Thus, while an outer peripheral portion of ring 36 seats to surface 35, an inner peripheral portion aligns with the inner peripheral portion of ring 28 and forms a continuing part of the materials flow channel.

At its inner periphery and at its end adjacent shoulder 34 the surface of ring 36 is inclined at 37 in the sense of the feed passages 33. The inclined surface por tion 37 provides a funnel to these passages, in rimming relation to their outer periphery. Entrance ring 36 is held to a seat on disc 21 by bolts 38, applied from the outer face of the ring through bores 39, the bolt heads being accommodated in counterbores 41 in such outer face.

At what may be considered its face most remote from the disc 21 refining surface, or its outer face which opposes the outer adjacent face of seal ring 28, the ring 36 is formed, intermediate its inner and outer peripheral portions, with an annular projecting rib or tongue 42. The orientation of the parts places the rib 42 in a penetrating, nesting, male-female relation to recess 32,

with respect to which it has a generally complementary configuration. The thickness of projection 42 is somewhat less in dimension than the width of recess 32 so that in assembled relation of the parts annular radially displaced spaces 43 and 44 are produced to the outer sides of the projection 42 within the recess 32. Further, the extent of the projection of the rib 42 from ring 36, taken with the extent of permitted approach between the sealing and entrance rings, provides at the bottom of recess 32 an annular, relatively deeper, chamber 45 which commonly communicates with the spaces 43 and 44 and orients perpendicularly thereof. The spacing of rings 28 and 36 still further provides, between opposing sides or faces thereof, inner and outer spaces 46 and 47 in parallel offset relation to chamber 45 and respectively communicating with remote ends of annular spaces 43 and 44. Space 46 opens into the flow channel to feed passages 33. Space 47 opens into a housing area Communicating with refining chamber 115. The entrance ring 36 accordingly is in a non-bearing, noncontacting relation to the sealing ring 23 with, however, the space therebetween forming a restricted, circuitous passageway made up of intercommunicating spaces 46, 43, chamber45 and spaces 44 and 47.

At circumferentially spaced locations, the sealing ring 28 is formed with through longitudinal bores 48, radially offset toward the inner peripheral portion of the ring. Thus at its one end each bore 48 opens simultaneously into chamber 45 and space 46. At their other ends, the bores 48 open upon shoulder 25 where, in re sponse to a suitable rotary positioning at the sealing ring, they align with other respective through bores 49 in housing wall ll. At their outer ends, bores 49 are internally threaded to facilitate a coupling thereto of conduit means delivering steam or another fluid under pressure. Desirably, the fluid is supplied at a pressure somewhat exceeding the expected high pressure established in chamber 15.

In the operation of the described embodiment, when the disc units are energized and a slurry in the form of fibrous solids embodied in a fluid vehicle is delivered to the refiner under required pressure, then the slurry will be moved directly through passage 16, inlet opening l2, past rings 28 and 36, and be funnelled to a central area intermediate the discs 21 and 22 by way of funnelling ring surface 37 and feed passages 33. The relative rotation of the discs will cause a radial outward movement of the slurry content to be refined between their operating faces.

During the slurry feed there will be directed to one side of the chamber 45 and to space 46 a fluid under pressure. The entire circuitous or deviating passageway between the relatively rotating rings 28 and 36 will be consequently flooded with pressure fluid, a major thrust of which is directed toward the space 26 immedi ately at the flow channel in a manner tending to deny entrance to the passageway of unrefined solids. At the same time, however, a continuing flow of fluid to the chamber 45 causes a portion thereof to move through spaces 43 and 46 to the chamber 15. As a result, if small shives (which are not objectionable) may have inadvertently achieved an entrance to spaces 46 and 43 they will be quickly moved from the joint thereby. Such solids would inherently be of negligible size and con cern due to the fluid block achieved by the joint as provided by the present invention.

It is inherent in the function of the pressurized joint as here provided that by reason of the offset positioning of the fluid delivery to the chamber area 45, a critical pressure block is provided within the joint between the seal ring 28 and the rotating ring 36 which inhibits the passage through the joint of unrefined solids in the course of their movement to the refining surfaces of the discs 21 and 22. By reason of the labyrinth form of the spacing between the rings 28 and 36 forming a fluid joint and the chamber areas created by such spacing, there is provided, in effect, a fluid dam in the chamber area 45 from which pressure fluid moves to and through the spaces 43, and 46, and 44 and 47. The width of the spaces 43, 44, 46 and 47 is of course quite limited in comparison to the depth of chamber 45. The net effect is a forceful interference with any unrefined solids that attempt to move from the delivery channel leading to the refiner disc 21. Moreover, if any materials do move into the fluid joint, they will inherently be of a nature of small shives which are picked up in the fluid movement and they will, if such shives reach the damarea 45, and are not ejected prior thereto, tend to be cleansed by the fluid movement therein and evacuated from the joint.

ltwill be readily obvious, therefore, and the same has been proven in test, that by means of the present invert tive concept there is absolutely minimized and substantially eliminated, in a simple manner, the serious problem of contamination of a refined product by reason of bypass of unrefined products at the inlet to a disc refiner of the class described. At the same time, the joint between the relatively rotating sealing and entrance rings is kept free of solids which might accumulate therein and cause a buildup of frictional forces. Of course it will also be just as obvious that the invention mayserve equally as well in other applications involving a feed problem of a similar nature. By appropriate choice of the fluid utilized as a pressure block in'the joint, one can avoid not only a contamination of the desired end product but also maintain the close clearance surfaces of the rings 28 and 36 in a lubricated state. This avoids wear, jamming and other mechanical difficulties which are detrimental to refiner operation and its cost of maintenance. The fluid used could be for example water, steam, or air.

A particular nesting relationship of the sealing and entrance rings has been disclosed. it will be evident that the invention contemplates other specific nesting constructions, particularly as it may be comprised in the combination of a feed joint and means to flood such joint with fluid under pressure.

The invention above disclosed has proven in test to have the unique advantage and results attributed. The burning of seals and contamination of products of double disc refining has been overcome. The net resultis reduction in maintenance costs and higher quality end products.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one of several modes of putting the invention into effect and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described our invention, we claim:

1. A disc refiner including a housing, a pair of relatively opposed refiner discs mounted for rotation within a chamber defined in said housing, one of said refiner discs including at least one feed passage for material to move between said discs to be refined thereby and discharged therefrom, said housing having means defining an inlet to said chamber and further means defining an outlet therefrom, said means defining said inlet and said one disc including complementary ring means forming a flow channel for directing the material to be refined to move to and through said disc feed passage, one of said ring means forming an axial extension being directed to open to said joint intermediate its extremities at a location to provide that the fluid exiting therefrom'under pressure will flow within said joint in respectively opposite directions to exert a blocking and cleansing influence in said joint.

2. Apparatus as set forth in claim 1 characterized by said adjacent faces being formed to have a nesting relation.

3. Apparatus as set forth in claim 1 characterized by an intermediate area of said joint being expanded relative the extremities thereof to provide a pressure chamber forming said space into which the fluid from said passage exits which inhibits passage of solid particles through said joint.

4. Apparatus as set forth in claim 1 characterized by the adjacent faces of said ring means defining said joint forming a restricted circuitous passageway from the extremities of which said fluid under pressure will simultaneously exit to block and cleanse said passageway.

5. A disc refiner including a housing, disc means mounted for rotation in said housing, means forming an inlet for directing material to be refined between said disc means, one of said disc means being adjacent said inlet and having at least one feed passage for material to pass therethrough to be refined between said disc means, relatively adjacent parts on said housing and said one of said disc means cooperating to define a flow channel leading from said inlet to said feed passage in said one disc means, said relatively adjacent parts being formed to have the adjacent ends thereof in a closely spaced relation and defining a labyrinth type passageway an inner radial limit of which opens to said flow channel and an outer radial limit of which opens to said housing, and means to simultaneously direct fluid under pressure to move from the radial limits of said passageway to exert both a blocking and ejecting influence on particles of material which attempt to move to and through said passageway from said flow channel.

6. A disc refiner according to claim 5 characterized in that the adjacent ends of said relatively adjacent parts being formed to relatively nest in a male-female relation forming a restricted circuitous passageway from the inner to the outer radial limits thereof an intermediate portion of which is relatively expanded to provide a chamber in which fluid under pressure may build up prior to exit simultaneously to the respective radial limits of said passageway. 7. A disc refiner including a housing, a pair of relatively opposed refiner discs mounted for rotation within a chamber defined in said housing, one of said refiner discs including at least one feed passage for material to move between said discs to be refined thereby and discharged therefrom, said housing having means defining an inlet to said chamber and further means defining an outlet therefrom, said means defining said inlet and said one disc including complementary ring means forming a flow channel for directing the material to be refined to move to and through said disc feed passage, one of said ring means being an axial extension of the other and adjacent faces of said ring means being in a closely spaced relation to define a low clearance area therebetween, one of said ring means having a passage therein for directing fluid therethrough under pressure to exit therefrom and produce a fluid joint between said adjacent faces of said ring means, said fluid joint opening at one extremity to said flow channel and at the other extremity to said chamber, one of said adjacent faces of said ring means having an annular groove and the other having a complementary mating annular projection which nests in said groove to define thereby an intermediate area within said joint to which said passage in said one of said ring means exits which area is so formed and positioned in said joint to provide that the fluid exiting under pressure will move in respectively opposite-directions to exert a blocking and cleansing influence in said joint whereby to inhibit passage of solid particles to and through said joint.

8. Apparatus as set forth in claim 7 characterized by the spacing between the projected extremity of said annular projection and the base of said annular groove being greater than the spacing of said adjacent faces at said extremities of said joint. 

1. A disc refiner including a housing, a pair of relatively opposed refiner discs mounted for rotation within a chamber defined in said housing, one of said refiner discs including at least one feed passage for material to move between said discs to be refined thereby and discharged therefrom, said housing having means defining an inlet to said chamber and further means defining an outlet therefrom, said means defining said inlet and said one disc including complementary ring means forming a flow channel for directing the material to be refined to move to and through said disc feed passage, one of said ring means forming an axial extension of the other, adjacent faces of said ring means being in a closely spaced relation, means providing a passage for directing fluid under pressure to move through one of said ring means and exit from one of said adjacent faces into the space between said faces to produce a fluid joint therebetween extending generally radially of said ring means, said fluid joint opening at one extremity to said flow channel and at the other extremity to said chamber, said passage through one of said ring means being directed to open to said joint intermediate its extremities at a location to provide that the fluid exiting therefrom under pressure will flow within said joint in respectively opposite directions to exert a blocking and cleansing influence in said joint.
 2. Apparatus as set forth in claim 1 characterized by said adjacent faces being formed to have a nesting relation.
 3. Apparatus as set forth in claim 1 characterized by an intermediate area of said joint being expanded relative the extremities thereof to provide a pressure chamber forming said space into which the fluid from said passage exits which inhibits passage of solid particles through said joint.
 4. Apparatus as set forth in claim 1 characterized by the adjacent faces of said ring means defining said joint forming a restricted circuitous passageway from the extremities of which said fluid under pressure will simultaneously exit to block and cleanse said passageway.
 5. A disc refiner including a housing, disc means mounted for rotation in said housing, means forming an inlet for directing material to be refined between said disc means, one of said disc means being adjacent said inlet and having at least one feed passage for material to pass therethrough to be refined between said disc means, relatively adjacent parts on said housing and said one of said disc means cooperating to define a flow channel leading from said inlet to said feed passage in said one disc means, said relatively adjacent parts being formed to have the adjacent ends thereof in a closely spaced relation and defining a labyrinth type passageway an inner radial limit of which opens to said flow channel and an outer radial limit of which opens to said housing, aNd means to simultaneously direct fluid under pressure to move from the radial limits of said passageway to exert both a blocking and ejecting influence on particles of material which attempt to move to and through said passageway from said flow channel.
 6. A disc refiner according to claim 5 characterized in that the adjacent ends of said relatively adjacent parts being formed to relatively nest in a male-female relation forming a restricted circuitous passageway from the inner to the outer radial limits thereof an intermediate portion of which is relatively expanded to provide a chamber in which fluid under pressure may build up prior to exit simultaneously to the respective radial limits of said passageway.
 7. A disc refiner including a housing, a pair of relatively opposed refiner discs mounted for rotation within a chamber defined in said housing, one of said refiner discs including at least one feed passage for material to move between said discs to be refined thereby and discharged therefrom, said housing having means defining an inlet to said chamber and further means defining an outlet therefrom, said means defining said inlet and said one disc including complementary ring means forming a flow channel for directing the material to be refined to move to and through said disc feed passage, one of said ring means being an axial extension of the other and adjacent faces of said ring means being in a closely spaced relation to define a low clearance area therebetween, one of said ring means having a passage therein for directing fluid therethrough under pressure to exit therefrom and produce a fluid joint between said adjacent faces of said ring means, said fluid joint opening at one extremity to said flow channel and at the other extremity to said chamber, one of said adjacent faces of said ring means having an annular groove and the other having a complementary mating annular projection which nests in said groove to define thereby an intermediate area within said joint to which said passage in said one of said ring means exits which area is so formed and positioned in said joint to provide that the fluid exiting under pressure will move in respectively opposite directions to exert a blocking and cleansing influence in said joint whereby to inhibit passage of solid particles to and through said joint.
 8. Apparatus as set forth in claim 7 characterized by the spacing between the projected extremity of said annular projection and the base of said annular groove being greater than the spacing of said adjacent faces at said extremities of said joint. 